Dietary Chinese herbal preparations improve growth performance, immune function, and gut health in weaned piglets.

INTRODUCTION: The search for effective antibiotic-free feed additives is critical for sustainable swine production. Compound Chinese herbal additives (CCHA) have attracted interest due to their potential bioactivity, but their optimal feeding concentration and duration for weaned piglets remain unclear. METHODS: A total of 210 healthy piglets aged 28 ± 1 days were randomly assigned to seven groups (control group-CON; 0.2%‑14d; 0.3%‑14d; 0.4%‑14d; 0.2%‑28d; 0.3%‑28d; 0.4%‑28d), with three replicates per group. Data from the six treatment groups were analyzed using two‑factor ANOVA within a general linear model, while one‑way ANOVA was applied for comparisons across all seven groups. Growth performance, nutrient digestibility, serum biochemical and immunological parameters, antioxidant capacity, and fecal microbiota composition were measured. RESULTS: Dietary CCHA supplementation significantly increased average daily gain (ADG) and average daily feed intake (ADFI) compared with CON (p < 0.01), though ADFI declined with extended feeding (p < 0.01). Crude protein (CP) digestibility improved (p < 0.05), while dry matter (DM) digestibility was significantly affected by feeding duration (p < 0.01). Serum total protein (TP), albumin (ALB), blood urea nitrogen (BUN), immunoglobulins, and total antioxidant capacity were all elevated in treated groups (p < 0.05). Prolonged feeding (28 d) further enhanced ADFI, CP and crude ash (ASH) digestibility, serum protein, immunoglobulin G (IgG), and total antioxidant capacity (T‑AOC), while reducing alanine transaminase (ALT) activity (p < 0.05). However, optimal concentrations varied: 0.2% favored growth, 0.3% benefited digestion and protein metabolism, whereas 0.4% showed inhibitory effects under long‑term feeding. Microbiota sequencing revealed increased abundances of Lactobacillus and Clostridiaceae in CCHA‑supplemented piglets. CONCLUSION: These findings indicate that CCHA can effectively improve growth performance, nutrient utilization, immune status, antioxidant capacity, and gut microbial composition in weaned piglets, thereby positioning it as a promising antibiotic‑free feed additive.